Since August, AP has been publishing stories from its ongoing investigation into secret intelligence operations set up by the New York Police Department following the Sept. 11, 2001 terror attacks.

AP’s investigation has revealed that the NYPD dispatched undercover officers into minority neighborhoods as part of a human mapping program. Police also used informants, known as “mosque crawlers,” to monitor sermons, even when there was no evidence of wrongdoing.

The AP also determined that police subjected entire neighborhoods to surveillance and scrutiny, often because of the ethnicity of the residents, not because of any accusations of crimes. Hundreds of mosques and Muslim student groups were investigated and dozens were infiltrated. Many of these operations were built with help from the CIA, which is prohibited from spying on Americans but was instrumental in transforming the NYPD’s intelligence unit after 9/11.

Click here to see the AP investigative team’s body of work to date.